Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-26T05:00:21.346Z Has data issue: false hasContentIssue false

SSX MHD plasma wind tunnel

Published online by Cambridge University Press:  17 March 2015

Michael R. Brown*
Affiliation:
Department of Physics and Astronomy, Swarthmore College, 500 College Ave. Swarthmore, PA 19081, USA
David A. Schaffner
Affiliation:
Department of Physics and Astronomy, Swarthmore College, 500 College Ave. Swarthmore, PA 19081, USA
*
Email address for correspondence: doc@swarthmore.edu

Abstract

A new turbulent plasma source at the Swarthmore Spheromak Experiment (SSX) facility is described. The MHD wind tunnel configuration employs a magnetized plasma gun to inject high-beta plasma into a large, well-instrumented, vacuum drift region. This provides unique laboratory conditions approaching that in the solar wind: there is no applied background magnetic field in the drift region and has no net axial magnetic flux; the plasma flow speed is on the order of the local sound speed (M ~ 1), so flow energy density is comparable to thermal energy density; and the ratio of thermal to magnetic pressure is of order unity (plasma β ~ 1) so thermal energy density is also comparable to magnetic energy density. Results presented here and referenced within demonstrate the new capabilities and show how the new platform is proving useful for fundamental plasma turbulence studies.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Alexandrova, O., Lacombe, C. and Mangeney, A. 2008 Spectra and anisotropy of magnetic fluctuations in the Earth's magnetosheath: cluster observations. Ann. Geophys. 26, 3585.CrossRefGoogle Scholar
Alexandrova, O., Saur, J., Lacombe, C., Mangeney, A., Mitchell, J., Schwartz, S. J. and Robert, P. 2009 Universality of solar-wind turbulent spectrum from MHD to electron scales. Phys. Rev. Lett. 103, 165003.CrossRefGoogle ScholarPubMed
Batchelor, G. K. 1970 Theory of Homogeneous Turbulence. Cambridge, England: Cambridge University Press.Google Scholar
Bellan, P. M. 1979 Spontaneous, three-dimensional, constant-energy implosion of magnetic mirror fields. Phys. Rev. Lett. 43, 858861.CrossRefGoogle Scholar
Bellan, P. M. 2000 Spheromaks. London, England: Imperial College Press.CrossRefGoogle Scholar
Bickerton, R. J. 1997 Magnetic turbulence and the transport of energy and particles in tokamaks. Plasma Phys. Control. Fusion 39, 339.CrossRefGoogle Scholar
Binderbauer, et al. 2010 Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high β compact toroids. Phys. Rev. Lett. 105, 045003.CrossRefGoogle ScholarPubMed
Brown, M. R. 1997 Experimental evidence of rapid relaxation to large scale structures in turbulent fluids: selective decay and maximal entropy. J. Plasma Phys. 57, 203.CrossRefGoogle Scholar
Brown, M. R. 1999 Experimental studies of magnetic reconnection. Phys. Plasmas 6, 1717.CrossRefGoogle Scholar
Brown, M. R., Cothran, C. D., Gray, T., Myers, C. E. and Belova, E. V. 2012 Spectroscopic observation of simultaneous bi-directional reconnection outflows in a laboratory plasma. Phys. Plasmas 19, 080704.CrossRefGoogle Scholar
Bruno, R. and Carbone, V. 2013 The solar wind as a turbulence laboratory. Living Rev. Sol. Phys. 10, 2. http://www.livingreviews.org/lrsp-2005-4CrossRefGoogle Scholar
Buchenauer, C. J. and Jacobson, A. R. 1977 Quadrature interferometer for plasma density measurements. Rev. Sci. Instrum. 48, 769774.CrossRefGoogle Scholar
Cothran, C. D., Brown, M. R., Gray, T., Schaffer, M. J. and Marklin, G. 2009 Observation of a helical self-organized state in a compact toroidal plasma. Phys. Rev. Lett. 103, 215002.CrossRefGoogle Scholar
Cothran, C. D., Fung, J., Brown, M. R. and Schaffer, M. J. 2006 Fast, high resolution Echelle spectroscopy of a laboratory plasma. Rev. Sci. Instrum. 77, 063504.CrossRefGoogle Scholar
Frisch, U. 1995 Turbulence: The Legacy of A.N. Kolmogorov. Cambridge, New York: Cambridge University Press.CrossRefGoogle Scholar
Frisch, U., Pouquet, A., Leorat, J. and Mazure, A. 1975 Possibility of an inverse cascade of magnetic helicity in magnetohydrodynamic turbulence. J. Fluid Mech. 68, 769778.CrossRefGoogle Scholar
Geddes, C. G. R., Kornack, T. W. and Brown, M. R. 1998 Scaling studies of spheromak formation and equilibrium. Phys. Plasmas 5, 1027.CrossRefGoogle Scholar
Gekelman, W. and Stenzel, R. 1984 J. Geophys. Res.-Space Phys. 89, 2715.CrossRefGoogle Scholar
Goldstein, M., Roberts, D. and Matthaeus, W. 1995 Annu. Rev. Astron. Astrophys. 33, 283, ISSN .CrossRefGoogle Scholar
Gray, T., Brown, M. R. and Dandurand, D. 2013 Observation of a relaxed plasma State in a quasi-infinite cylinder. Phys. Rev. Lett. 110, 085002.CrossRefGoogle Scholar
Gray, T., Lukin, V. S., Brown, M. R. and Cothran, C. D. 2010 Three-dimensional reconnection and relaxation of merging spheromak plasmas. Phys. Plasmas 17, 102106.CrossRefGoogle Scholar
Greco, A., Chuychai, P., Matthaeus, W. H., Servidio, S. and Dmitruk, P. 2008 Intermittent MHD structures and classical discontinuities. Geophys. Res. Lett. 35, L19111. doi:10.1029/2008GL035454.CrossRefGoogle Scholar
Greco, A., Matthaeus, W. H., Servidio, S., Chuychai, P. and Dmitruk, P. 2009 Statistical analysis of discontinuities in solar wind ACE data and comparison with intermittent MHD turbulence. Astrophys. J. 691, L111. doi:10.1088/0004-637X/691/2/L111.CrossRefGoogle Scholar
Guo, H.et al. 2004 Flux conversion and evidence of relaxation in a high β plasma formed by high-speed injection into a mirror confinement structure. Phys. Rev. Lett. 92, 245001.CrossRefGoogle Scholar
Hooper, E. B.et al. 2012 Sustained Spheromak Physics Experiment (SSPX): Design and physics results. Plasma Phys. Control. Fusion 54, 113001.CrossRefGoogle Scholar
Hutchinson, I. H. 2002 Principles of Plasma Diagnostics, 2nd edn.Cambridge, England: Cambridge University Press.CrossRefGoogle Scholar
Kolmogorov, A. N. 1941 The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers. Dokl. Acad. Nauk. SSSR 30, 301.Google Scholar
Landreman, M., Cothran, C. D., Brown, M. R., Kostora, M. and Slough, J. T. 2003 Rapid multiplexed data acquisition: application to three-dimensional magnetic field measurements in a turbulent laboratory plasma. Rev. Sci. Instrum. 74, 2361.CrossRefGoogle Scholar
Lee, E., Brachet, M. E., Pouquet, A., Mininni, P. D. and Rosenberg, D. 2010 Lack of universality in de- caying magnetohydrodynamic turbulence. Phys. Rev. E 81 (1), 016318.CrossRefGoogle Scholar
Matthaeus, W. H. and Montgomery, D. 1980 Ann. N.Y. Acad. Sci. 357, 203.CrossRefGoogle Scholar
Matthaeus, W. H. and Velli, M. 2011 Who needs turbulence. Space Sci. Rev. 160, 145.CrossRefGoogle Scholar
Nornberg, M. D., Spence, E. J., Kendrick, R. D., Jacobson, C. M. and Forest, C. B. 2006 Measurements of the magnetic field induced by a turbulent flow of liquid metal. Phys. Plasmas 13, 055901.CrossRefGoogle Scholar
Pouquet, A., Frisch, U. and Leorat, J. 1976 Strong MHD helical turbulence and nonlinear dynamo effect. J. Fluid Mech. 77, 321354.CrossRefGoogle Scholar
Ren, Y., Almagri, A. F., Fiksel, G., Prager, S. C., Sarff, J. S. and Terry, P. W. 2011 Phys. Rev. Lett. 107, 195002.CrossRefGoogle Scholar
Roberts, D. A. 2010 Evolution of the spectrum of solar wind velocity fluctuations from 0.3 to 5AU. J. Geophys. Res. 115, A121101.CrossRefGoogle Scholar
Sahraoui, F., Belmont, G., Rezeau, L., Cornilleau-Wehrin, N., Pincon, J. L. and Balogh, A. 2006 Anistropic turbulent spectra in the terrestrial magnetosheath as seen by the cluster spacecraft. Phys. Rev. Lett. 96, 075002.CrossRefGoogle Scholar
Sahraoui, F., Goldstein, M., Robert, P. and Khotyaintsev, Y. 2009 Evidence of a cascade and dissipation of solar-wind turbulence at the electron gyroscale. Phys. Rev. Lett. 102 (23), 231102.CrossRefGoogle ScholarPubMed
Schaffner, D. A., Brown, M. R. and Lukin, V. S. 2014c Temporal and spatial turbulent spectra of MHD plasma and an observation of variance Anisotropy. Astrophys. J. 790, 126.CrossRefGoogle Scholar
Schaffner, D. A.Lukin, V. S., Wan, A. and Brown, M. R. 2014a Turbulence analysis of an experimental flux rope plasma. Plasma Phys. Contol. Fusion 56, 064003.CrossRefGoogle Scholar
Schaffner, D. A., Wan, A. and Brown, M. R. 2014b Observation of turbulent intermittency scaling with magnetic helicity in an MHD plasma wind tunnel. Phys. Rev. Lett. 112, 165001.CrossRefGoogle Scholar
Servidio, S., Matthaeus, W. H. and Dmitruk, P. 2008 Depression of nonlinearity in decaying isotropic MHD turbulence. Phys. Rev. Lett. 100, 095005. doi:10.1103 Phys. Rev. Lett.100.095005.CrossRefGoogle ScholarPubMed
Servidio, S.et al. 2011a Magnetic reconnection as an element of turbulence. Nonlinear Process. Geophys. 18, 675.CrossRefGoogle Scholar
Servidio, S.et al. 2011b Statistical association of discontinuities and reconnection in magnetohydrodynamic turbulence. J. Geophys. Res. 116, A09102.CrossRefGoogle Scholar
Taylor, J. B. 1974 Relaxation of Torodial Plasma and Generation of Reverse Magnetic Fields. Phys. Rev. Lett. 33, 1139.CrossRefGoogle Scholar
Tsurutani, B. T. and Smith, E. J. 1979 Interplanetary discontinuities - Temporal variations and the radial gradient from 1 to 8.5 AU. J. Geophys. Res. 84, 2773.CrossRefGoogle Scholar
Turner, W.et al. 1983 Investigations of the magnetic structure and the decay of a plasma gun generated compact torus. Phys. Fluids 26, 1965.CrossRefGoogle Scholar
Yordanova, E., Vaivads, A., Andre, M., Buchert, S. C. and Voros, Z. 2008 Magnetosheath plasma turbulence and its spatiotemporal evolution as observed by the cluster spacecraft. Phys. Rev. Lett. 100, 205003.CrossRefGoogle ScholarPubMed
Zhang, X., Dandurand, D., Gray, T., Brown, M. R., and Lukin, V. S. 2011 Calibrated cylindrical mach probe in a plasma wind tunnel. Rev. Sci. Instrum. 82, 033510.CrossRefGoogle Scholar